The preset invention relates in general to authentication of a person by detecting individual biometric features of said person and comparing them with corresponding, previously stored biometric features of the same person. In particular, the invention relates to a method for biometric authentication of a person, an apparatus used in this connection—for example a data carrier such as a smart card, etc.—and a system comprising such an apparatus and devices for detecting and comparing the biometric features.
For biometric authentication, a persons biometric features, for example a finger-print, are checked by detecting the biometric feature and comparing it for sufficient similarity with a previously stored biometric feature. Positive comparison grants said person access to data, admission to rooms and similar measures protected from unauthorized access. The biometric features stored as reference data can be stored in any apparatus, for example a fingerprint door opener, or be portable by being stored in a smart card such as a money card, credit card, ID card and the like.
Biometric data can usually not be determined in precisely reproducible fashion, so that a match of stored reference data with currently measured comparative data is virtually impossible. For this reason the result of comparison is fixed as already positive if the match of the compared data exceeds a general threshold value, for example if only a 50 percent match is ascertained.
A disadvantage here is that the detection quality of biometric features varies from person to person. For example, the measuring result of a fingerprint is worse in the case of dry skin or very moist skin. Therefore, the threshold value is usually set altogether very low in order to be permit reliable authentication of all persons. However, a low threshold value simultaneously means a low security standard for access-protected facilities.